Lab 1 Silicone and Zener Diodes Characteristics v2!2!1112.Docx

8/11/2019 Lab 1 Silicone and Zener Diodes Characteristics v2!2!1112.Docx

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COURSE CODE: EXPERIMENT NO: 1

COURSE INSTRUCTOR: DATE:

TITLE: MARKS

OBJECTIVE:

PRELAB :

1a /0.5

1b /0.5

2a /0.5

2b /0.5

/ 2

EXPERIMENT RESULT:

Part A : Silicon Diode

Table 1-1 /2

Table 1-2 /2

Forward-biased graph /2

Reversed-biased graph /2

Part B : Zener Diode

/2

Zener diode graph /2

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POST LAB:

Question 1:

a /1

b /1

Question 2:

a /1

b /1

c /1

/ 5

CONCLUSION: / 1

INSTRUCTOR COMMENTS: TOTAL

/20

Table 1-3

Semester: 2 Academic Year: 2011 / 2012

TIME:

STUDENT NAME: STUDENT ID:

SECTION:

WORKBENCH NO:GROUP MEMBER: STUDENT ID:

UNIVERSITI TENAGA NASIONAL

Dept of Electronics and Communication Engineering

College of Engineering

EEEB141

Silicone & Zener Diode Characteristics

The objectives of this laboratory experiment are to study the I-V characteristics for normal and zener diodes


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EEEB 141ELECTRONICS DESIGN LAB, Lab 1 1

LAB 1 SILICONE &ZENER DIODES CHARACTERISTICS

LEARNING OBJECTIVES

By the end of this experiment, you should be able to:

Measure and plot the forward and reverse-biased characteristics for a diode.

Measure and plot the characteristics for Zener diodes.

MATERIALS

Resistors: 1 330, 1 1.0M, 5605W

Components: 1 1N4148 or equivalent, 1 1N4740

EQUIPMENT

Tektronix PS280 DC Power Supply

Fluke 45 Dual Display Multimeter

PRE-LAB ASSIGNMENT

Answer the following questions:

1. Silicon Diode Characteristics

a. The semiconductor diode is basically a pn junction. Draw a simple diagram to

show the cross section of the diode. On the diagram, indicate

thepand nregions

as well as the anode and the cathode of the diode.

b. Sketch

the I-V characteristic of an ideal diode.


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2.

Zener Diode

a. Sketch

the general I-V Zener diode characteristics indicating all important

points.

b. State two

differences between normal diodes and Zener diodes.


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BACKGROUND

Diode is a device formed from a junction of p-type and n-type semiconductor materials. The

lead connected to the p-type material is called anode while the lead connected to the n-

type material is called cathode. Normally, the cathode of a diode is marked by a solid line

on the diode.

One important application of diode is rectification. When it is forward biased (higher

potential connected to the anode), the diode will allow current to pass. When it reversed

biased (higher potential connected to the cathode), the current is almost zero or blocked.

The diode can be thought of a switch that closes (on) when the diode is forward biased, and

opens (off) when diode is reversed biased.

Another important characteristic of a diode is the reverse bias breakdown. Applied reverse

bias voltage cannot increase without limit. At some point, breakdown occurs and the

reverse-bias direction increases rapidly. Breakdown may damage to a normal diode.

However, diodes called Zener diodes can be designed and fabricated to provide a specific

breakdown point.

IN-LAB ACTIVITIES

PART A (Normal Diode- Characteristic)

1. Measure and record the resistance of the resistors. Then check your diode with the

multi-meter. Measure the forward and reverse resistances of the diode. Record and

tabulate the data.

2. Construct the forward-biased circuit shown in Figure 1-1. Set the power supply for

zero volts.

CathodeAnode

Forward Bias

Region

Reverse Bias

RegionReverse Bias

Breakdown Region

I

V


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Figure 1-1

3. Monitor the forward voltage drop, VD,FOR, across the diode, D1. Slowly increase VS

to establish 0.35V across the diode. Measure the voltage across the resistor, VR1,

and compute ID FOR

. Record and tabulate the data in Table 1-1.

4. Repeat step 3 for voltage VD,FOR of 0.40V, 0.45V, 0.50V, 0.55V, 0.60V, 0.65V,

0.70V, and 0.75V.

5. Connect the reverse-biased circuit shown in Figure 1-2. Set the power supply, VSto

5.0V, and then to 10.0V, 15.0V, 20.0V, and 25V. Measure VD REV and compute

ID,REVfor each voltage applied. Record and tabulate the data in Table 1-2.

Figure 1-2


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RESULTS

Resistor Resistances

R330:

R1M: M

Diode Resistances

Forward bias: M

Reverse bias: M

VD,FOR(V)

VS (V) VR1(V)1

R1

D

R

VI = (A)

Nominal Measured

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

Table 1-1

VS (V)

VR1(V) VD,REV(V)1

R1

D

R

VI = (A)

Nominal Measured

5

10

15

20

25

Table 1-2


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PART B (Zener Diode characteristic)

1. Build the circuit shown in Figure 1-3 using a 5.0V Zener diode.

Figure 1-3

2. Monitor Vin and Vout and record Vout for Vin values from 0 10V at intervals of

0.5V.

3. Record your results in Table 1-3.

4. Plot graphs of current, I against the output voltage, Vo for the Zener diode on a

graph paper.


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RESULTS

Vin

(V)

Vout

(V)

VR

(V)R

VI

R=

(mA)

Vin

(V)

Vout

(V)

VR

(V)R

VI

R=

(mA)

0.5 5.5

1.0 6.0

1.5 6.5

2.0 7.0

2.5 7.5

3.0 8.0

3.5 8.5

4.0 9.0

4.5 9.5

5.0 10.0

Table 1-3


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POST LAB DISCUSSIONS

1. Silicon Diode Characteristic

a. Describe your observation/understanding based on the plotted forward biased

diode curve graph.

b. Discuss the difference from the experimental I-V plot, compared to the ideal diode

I-V characteristic drawn in the pre-lab question.

2. Zener Diode Characteristic

a. Describe your observation based on the plotted I-V graph in Part B.

b.

If the same experiment was repeated using a 10.0 V Zener Diode, explain the

expected resulting I-V characteristic. Sketch the expected I-V graph.

c. Name an example of possible application of a Zener diode? Explain briefly.

CONCLUSIONS


10/12Free Plain Graph Paper from http://incompetech.com/graphpaper/plain/


11/12Free Plain Graph Paper from http://incompetech.com/graphpaper/plain/


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Lab 1 Silicone and Zener Diodes Characteristics v2!2!1112.Docx

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